1 / 32

Reactions of Synthesis and Decay Properties of Superheavy Elements

HEAVIEST COMPOUND NUCLEI. Reactions of Synthesis and Decay Properties of Superheavy Elements. Yuri Oganessian Flerov Laboratory of Nuclear Reactions Joint Institute for Nuclear Research 141980 Dubna, Moscow region, Russia. Third International Workshop on Compound-Nuclear Reactions

ama
Download Presentation

Reactions of Synthesis and Decay Properties of Superheavy Elements

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. HEAVIEST COMPOUND NUCLEI Reactions of Synthesis and Decay Properties of Superheavy Elements Yuri Oganessian Flerov Laboratory of Nuclear Reactions Joint Institute for Nuclear Research 141980 Dubna, Moscow region, Russia Third International Workshop on Compound-Nuclear Reactions and Related Topics (CNR*11) September 19-23, 2011, Prague, Czech Republic

  2. Macroscopic theory (charged liquid drop model) TSF ≈ 10-7a 102No / Tα≈ 2 s. Z=106? Th Bi 92U / Tα= 4.5·109a TSF = 1.0·1016a 82Pb / stable

  3. …and Half - Lives Predictions of the microscopic theory Predictions of the microscopic theory Fission Barriers R. Smolańczuk, Phys. Rev. C 56 (1997) 812 Yuri Oganessian “Heaviest Compound-Nuclei”(CNR*11) , September 19-23, 2011, Prague, Czech Republic

  4. -5 0 5 10 15 LogT1/2 s New lands New lands New lands New lands 1µs 1s 1h 1 Ma a 120 r e b m u 110 n n o t o r P 100 90 80 70 150 170 100 110 130 140 190 120 160 180 Neutron number Microscopic theory 116 114 Отмель 106 Peninsula Island of Stability continent Sea of Instability

  5. Reaction of Synthesis

  6. Reactions of synthesis Act.+48Ca Cold fusion Light ions target from “peninsula” Neutron capture target from “continent” Yuri Oganessian “Heaviest Compound-Nuclei”(CNR*11) , September 19-23, 2011, Prague, Czech Republic

  7. Compound nuclei excitation energy at the Coulomb barrier

  8. Reactions of Synthesis Reactions of Synthesis spherical nuclei deformed nuclei SHE Fusion of massive Ions with Pb-target nuclei Since 1975 Cold fusion Light ion fusion with Act.-nuclei Hot fusion actinides Pb protons → Neutron capture neutrons → Yuri Oganessian “Heaviest Compound-Nuclei”(CNR*11) , September 19-23, 2011, Prague, Czech Republic

  9. Cold fusion cross sections and fusion probability Cold fusion cross sections and fusion probability Z=112-118 Z=112-118 Act.+48Ca Ex=40-45 MeV Hot fusion Ex=12-15 MeV Cold fusion 1 event / year SHE

  10. Cross sections Cross sections Yu. Oganessian 2011 σxn ~ (Γn / Γf)x; х –number of neutrons (Γn / Γf) ~ exp(Bf – Bn) Bf= BfLD+ ΔEShell 0

  11. Reactions of Synthesis Reactions of Synthesis Cold fusion Cold fusion Act.+48Ca Act.+48Ca Neutron capture Neutron capture Hot fusion Hot fusion SHE protons → Intense ion beam of the rare isotope - 48Са Targets from the n-rich isotopes of the elements heavier than 238U Pb neutrons → Yu. Oganessian “Nuclei from Island of Stability of SHE” M-Lakes Conference Sept. 11-18, 2011, Poland

  12. Decay chains Decay chains Talk at the Meeting of RAS, Nov.,2000 244Pu, 248Cm +48Ca Z=116 0.06 s 2.5 s 114 114 Spherical shells 0.5 min 112 0.7 ms 11s 170μs 110 184 Deformed shells Yu. Oganessian 2011

  13. Confirmations2007-2010 Yuri Oganessian “Heaviest Compound-Nuclei”(CNR*11) , September 19-23, 2011, Prague, Czech Republic

  14. Odd-Z Superheavy Nuclei Synthesis of Isotopes with Z =113, 115 and 117 in 2010

  15. RAPID COMMUNICATIONS Yu. Ts. Oganessian et al., PRC 69, 021601(R) (2004) Experiments on the synthesis of element 115 in the reaction 243Am(48Ca, xn)291−x115 spherical deformed Yu. Oganessian 2011

  16. Synthesis of Element 117 Reaction: 249Bk + 48Ca → 297117* → 294-293117 + 3-4n T1/2=320d Yu. Oganessian 2010 high neutron flux HFIR(ORNL) high beam intensity of 48Ca-projectiles U-400 (JINR) High efficiency of separation 1 SH-atom/1012 products DGFRS

  17. The Bk-249 was produced at ORNL (USA) by irradiation: of Cm and Am targets for approximately 250 days by thermal-neutron flux of 2.5  1015 n/cm²·s in the HFIR (High Flux Isotope Reactor).  Yu. Oganessian 2010 Total dose: 4.3  1022 n/cm² Yuri Oganessian “Heaviest Compound-Nuclei”(CNR*11) , September 19-23, 2011, Prague, Czech Republic

  18. Yu. Oganessian 2010 50 Ci 50 Ci 22.2 mg of Bk-249 Yuri Oganessian “Heaviest Compound-Nuclei”(CNR*11) , September 19-23, 2011, Prague, Czech Republic

  19. Beam dose: 2.4·1019 Yu. Oganessian 2010

  20. Dubna Gas-Filled Recoil Separator Dubna Gas-Filled Recoil Separator Experimental technique Transmission for: EVR 35-40% target-like 10-4-10-7 projectile-like 10-15-10-17 Registration efficiency: for α-particles 87% for SF single fragment 100% two fragments ≈ 40% beam 48Ca target

  21. Yu. Oganessian 2011 1 events of decay of odd-odd isotope294117 and 5 events of decay of isotope 293117 were observed in this experiment Number of random sequences imitating such decay chain is: 3·10-11

  22. 6 new superheavy elements 118 117 116 115 114 Yu. Oganessian 2010 113 112 249Bk +48Ca 111 T1/2= 320d 110 109 48 new isotopes 108 107 106 105 104 Yuri Oganessian “Heaviest Compound-Nuclei”(CNR*11) , September 19-23, 2011, Prague, Czech Republic

  23. Decay Properties

  24. Yu. Oganessian 2011

  25. Calculated fission barrier heights P. Moller et al., Phys. Rev., C79, 064304 (2009) Yu. Oganessian 2011 ▼ Z=117 ▼ ▼ ▼ ▼ ▼ ▼ 113 spherical ▼ cold fusion ▼ Z=112 ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ 110 108 deformed Yuri Oganessian “Heaviest Compound-Nuclei”(CNR*11) , September 19-23, 2011, Prague, Czech Republic

  26. Total evaporation residues cross sections (pb) 100000 10000 Cross sections Cross sections Yu. Oganessian 2011 1000 100 SHE 10 48Ca-induced reactions 1 Cold fusion factor ~300 0.1 0.01 100 105 110 115 120 Atomic number

  27. ▼ Z=117 ▼ ▼ ▼ ▼ ▼ Z=112 ▼ alpha decay spontaneous fission Yu. Oganessian 2011 spherical deformed Yuri Oganessian “Heaviest Compound-Nuclei”(CNR*11) , September 19-23, 2011, Prague, Czech Republic

  28. Spontaneous fission half-lives Spontaneous fission half-lives “critical” zones Actinides Trans-actinides Superheavy nuclei 48Ca-induced reactions

  29. Half-lives of nuclei with Z ≥ 110 Half-lives of nuclei with Z ≥ 110 available for chemical studies N=162 Yu. Oganessian 2011 Act. + 48Ca Yuri Oganessian “Heaviest Compound-Nuclei”(CNR*11) , September 19-23, 2011, Prague, Czech Republic

  30. With Z >40% larger than that of Bi, the heaviest stable element, we see an impressive extension in nuclear survival. • Although SHN are at the limits of Coulomb stability, • shell stabilization lowers ground-state energy, • creates a fission barrier, • and thereby enables SHN to exist. The fundamentals of the modern theory for mass limits of nuclear matter were given experimental verification.

  31. Electronic structure of SHE-atoms Nuclear theory Atomic Physics Search for new shells Chemical properties of the SHE Chemistry Nuclear structure and decay properties of the SHN Nuclear Physics protons → A=294 Search for SHE in Nature Astrophysics Z=118 N=174 T1/2=1 ms Z=117 N=175 T1/2=100 ms neutrons → Yuri Oganessian “Heaviest Compound-Nuclei”(CNR*11) , September 19-23, 2011, Prague, Czech Republic

  32. Collaboration Thank you Yu. Oganessian 2010 FLNR, JINR (Dubna) ORNL (Oak-Ridge, USA) LLNL (Livermore, USA) RIAR (Dimitrovgrad, Russia) Vanderbilt University (Nashville, USA)

More Related